APPROXIMATE NONLINEAR OPTIMAL SDRE TRACKING CONTROL

The intrinsic nonlinearities of aircraft dynamics become exceptionally significant when there are demands for large maneuvers, causing aircraft to operate near the stability limits of the system, where series problems can be encountered, since the real issue becomes dealing with nonlinearities that dominate system behavior. This has eminent consequences in aerospace applications where catastrophic failure in high-performance aircraft must be prevented. Recently, a novel algorithm has been derived for nonlinear suboptimal tracking control, which can be realized for real-time computer implementation. The algorithm is based on the State-Dependent Riccati Equation (SDRE) strategy that has become well-known within the control community. This paper focuses on illustrating the application, computational advantage and validity of the proposed tracking control methodology on a realistic simulation example of a ducted fan engine model for high-performance thrust-vectored aircraft. The proposed method delivers a computationally simple, yet effective, algorithm for constructively synthesizing nonlinear suboptimal feedback controls for trajectory tracking problems.